Apparatus for drawing the isometric perspective view of an object

ABSTRACT

Apparatus enabling the isometric perspective of an object to be drawn from flat views of the object, including a fixed support on which the flat views of the object are provided, a rotatable support for a drawing sheet and positionable in one of three positions spaced by 120*, a follower for following a flat view, a tracer displacable over the rotatable support and means linking the follower and tracer such that displacements of the follower in two perpendicular directions cause displacements of the tracer which are perpendicular but in the ratio of one over the square root of three, the linkage means for displacements in one reference direction comprising rotary means, the effective diameters if which are in the ratio of one over the square root of three.

United States Patent 1191 Dangay, deceased et al.

[ 1 Jan. 22, 1974 APPARATUS FOR DRAWING THE [54] 2,645,016 7/1953 Nrobel 33/23 B ISOMETRIC PERSPECTIVE VIEW OF AN 2,553,026 5/1951 Williams et al. 33/18 C OBJECT FOREIGN PATENTS OR APPLICATIONS [76] Inventors; Jean Louis Dangay, deceased, lat f 52,300 l/l967 Poland 33/77 4 rue Alfred de Musset, Hauts dc K1173? 10/ germagv.... g

reat ntaln 33 2:; f z ifz xi fig 974,678 1011950 France 33/23 B France; pp g y, 79 81 741,554 12/1955 Great Bntam 33/18 C avenue P. Brossolette Hauts de H N. H Seine, France; Catherine Dangay, Prlmary Examiner my atom" 74 rue Gabriel Peri, Hauts de Seine, [57] ABSTRACT France heirs Apparatus enabling the isometric perspective of an Flledi J 1972 object to be drawn from flat views of the object, in-

[21] APPL 268 124 eluding a fixed support on which the flat views of the object are provided, a rotatable support for a drawing sheet and positionable in one of three positions spaced [30] Forelgn Application Priority Data by 120, a follower for following a flat view, a tracer June 30, 1971 'France 7123910 displacable over the rotatable support and means linking the follower and tracer such that displacements of [52] [1.8. CI 33/23 B, 33/18 C h follower in w perpendicul r irections cause dis- [51] Int. Cl. B43] 13/14 pl m nts of the tracer which are perpendicular but [58] Field of Search 33/23 B, 23 C, 18 C, 77 in the ratio of one over the square root of three, the

linkage means for displacements in one reference di- [56] References Cited rection comprising rotary means, the effective diame- UNITED STATES PATENTS ters if which are in the ratio of one over the square 1,684,887 9/1928 Ridgway 33123 B three 3,269,014 8/1966 Gase 33/18 C 10 Claims, 14 Drawing Figures l v --1 I PATENIEUJAHPPPW 3.786567 SHiH S [If 6 APPARATUS FOR DRAWING THE ISOMETRIC PERSPECTIVE VIEW OF AN OBJECT French patent No. 7010890 relates to an apparatus for drawing the isometric perspective view of an object from flat views of this object. This apparatus includes a fixed support upon which flat views of the object to be drawn may be formed or placed, a rotatable support for a drawing sheet, which may be placed in three angular positions spaced 120 apart, a follower for following a line on one of the flat views and a tracer which may be moved over the rotating support, the follower and the tracer being connected to each other such that displacements of the follower in two perpendicular reference directions causes displacements of the tracer, which are also perpendicular but are in a ratio to each other of one over the square root of three. This apparatus enables the isometric perspective view of an object to be drawn from three flat views along three directions at right-angles to each other (for example plan, elevation and end view), each of the positions of the rotating support corresponding to one of the flat views.

An object of the present invention is to create, for an apparatus of the above-mentioned type, a linkage mechanism between the follower and the tracer, which is simple, efficient and compact. A further object of the invention is to enable this mechanism to be arranged in such a manner that it may be used, without auxiliary calculations, to effect height transfers, i.e. to draw the perspective views of lines in the planes parallel to the flat view followed by the follower.

According to the present invention there is provided apparatus enabling the isometric perspective of an object to be drawn from flat views of the object including a fixed support on which flat views of the object to be drawn may be provided, a rotatable support for a drawing sheet which may be placed in one of three angular positions spaced by 120, a follower for following one of the flat views and a tracer which is displaceable over said rotatable support, said follower and said tracer being linked to each other in such a way that displacements of said follower in two perpendicular reference directions cause displacements of said tracer which are perpendicular but in the ratio of one over the square root of three, wherein said linkage between said follower and said tracer for displacements in that reference direction for which the displacements of said follower and said tracer are not equal is accomplished by means of rotary means, the effective diameters of which are in the ratio to each other of one over the square root of three.

Advantageously, the follower and the tracer are each mounted on a carriage caused to move along a rule which is slidable perpendicularly to its length. The two carriages may be mounted on the same rule or on different rules.

The height transfer device essentially comprises an appendage such as a set square, having an edge parallel to the table and at 45 to the direction of the rule along the carriage carrying the follower is slidable, a preferably adjustable stop enabling the said rule to be stopped in a fixed position and a locking device by means of which the carriage of the follower may be immobilised on the rule at any required position.

A method of height transfer using the above apparatus comprises providing on said table a flat view of the object to be drawn for which the mutually parallel planes in which the lines to be drawn are situated are perpendicular to the plane of the said view, said view being oriented such that the direction of said planes is parallel to said 45 edge, said follower bearing, rule against said stop, bringing said 45 edge into coincidence with the direction of one of said planes and locking said follower-bearing carriage on said rule and then, by displacing said rule, transferring one or more points in this plane on to an auxiliary view on which the line or lines to be drawn appear in full size, repeating the above process for each plane to draw an auxiliary view and, after release of said follower-bearing carriage, following this auxiliary view with said follower, said tracer simultaneously drawing the perspective view of the object.

Further features and advantages of the present invention will become apparent from the following description of embodiments thereof, given by way of example only, with reference to the accompanying drawings.

In the drawings:

FIG. 1 is a diagrammatic plan view of an embodiment of apparatus according to the present invention;

FIG. 2 is a large-scale, partial section along the line Il-II of FIG. 1;

FIG. 3 is a plan view on a larger scale of the support of the tracer of the embodiment of FIG. 1;

FIG. 4 is a section along the line lV--IV of FIG. 3;

FIG. 5 is a diagrammatic plan view of another embodiment or apparatus according to the present invention;

FIG. 6 is a detailed cross section along the line VIVI of FIG. 5; I

FIG. 7 is a diagrammatic plan view of a further embodiment of apparatus according to the present invention;

FIG. 8 is a plan view and FIG. 9 an end view illustrating a method of mounting the set-square on the follower carriage of the embodiment of FIG. 7;

FIGS. 10 and 11 are detailed sections in perpendicular planes of a device for locking the carriage of FIG. 7 on the rule;

FIG. 12 is a plane view and FIG. 13 a side view of the adjustable and removable stop for the table of the embodiment of FIG. 7; and

FIG. 14 is a view similar to that of FIG. 1 showing a further embodiment of apparatus according to the present invention.

In FIG. 1, the apparatus, of which only the drawing table I fitted with its rotating support 1a has been shown in order to simplify the description, includes, along one of the sides of the table 1, a fixed rule 2 on which a carriage 3 is slidable, the carriage 3 being rigidly fixed to a rule 4 extending perpendicularly to the rule 2. The end of rule 4 opposite to the one by which it is attached to the carriage 3 is provided with a wheel 5 which rests on the table.

Two carriages 6 and 7, respectively carrying a tracer 8 and a follower 9, are slidable along rule 4.

These two carriages 6, 7 are connected by a mechanism which includes a rack 10 rigidly attached to carriage 6, a rack 11 rigidly attached to carriage 7 and a double pinion 12 mounted on a shaft 13 rigidly mounted on a support 14 attached to rule 4. Pinion 12 is provided with two sets of teeth 12a, 12b (FIG. 2); the teeth 12a of smaller radial extent engage rack 10 and the teeth 12b of larger radial extent engage rack 11. The ratio of the effective diameters of the two sets of teeth is one over the square root of three and this is, therefore, also the ratio of the displacements of the tracer and the follower parallel to rule 4. Therefore, when the follower follows for example a circle, the tracer describes an ellipse the large axis of which is equal to the diameter of the circle and the small axis of which is equal to the product of this diameter and one over the square root of three (approximately 0.5774).

Tracer 8 is attached to carriage 6 by a doubly hinged arm 15, which is illustrated in FIGS. 3 and 4. The portion of arm 15 which carries the tracer is hinged to the other portion by means of a shaft 16, the lower end of which carries a ball-bearing 17 which is designed to run on the drawing sheet 18, and the upper end of which is provided with a nut 19 for locking the joint.

The said other portion of the arm is hinged to carriage 6 by means of a tubular shaft 20 and a lock-nut 21. The portions of the arm 15 are locked in the required position by means of the nuts 19 and 21. The tracer 8 may be arranged so as to be normally spaced from the paper and associated with an electro-magnet which causes it to rest on the paper during drawing. The follower may also be mounted on a similar hinged arm.

In the embodiment of FIGS. and 6 two rules 22 and 23 are provided parallel to each other and perpendicular to rule 2. The rules 22, 23 carry respectively the carriage 6 of the tracer 8 and the carriage 7 of the follower 9. The two rules 22, 23 form part of a frame of which one of the cross-members is formed by carriage 3 which slides on rule 2. The other cross-member, 25, is situated at the opposite end of the frame, as are support wheels 5.

A linkage between carriages 6 and 7 is provided by two cables 26 and 27.

These cables are wound respectively on coaxial drums 28 and 29 which are rigidly coupled for rotation and the shaft 30 of which is mounted between two pointed members 31 on two arms 32 with which carriage 3 is provided. The cables also pass around freerunning pulleys 33 and 34 respectively provided at the free-ends of rules 22 and 23.

The ratio of the effective diameters of drums 28 and 29 is equal to one over the square root of three, which ensures the same ratio for displacements of carriage 6 and carriage 7 along rules 22 and 23.

As is shown in FIG. 6, drum 29 includes an elongate hub 35 terminating in a firction disc 36 around which is mounted drum 28, the periphery of which is threaded. A threaded tightening ring 37 on the hub enables drum 28 to be keyed on drum 29 in any angular position in order to adjust the respective initial positions of the tracer and the follower. The drums are mounted on shaft 30 by means of bearings 38.

As in the preceding embodiment, when the follower describes a circle, the tracer describes an ellipse, the axes of which have the dimensions indicated above.

The double adjustment ability provided by the hinged arm of the first embodiment and by the friction mounting 36, 37 of the second embodiment enables the whole of the drawing table to be covered.

In the embodiment of FIG. 7, the apparatus, as for the preceding embodiments, includes a drawing table 1 having a rotating support la and a follower and a tracer connected to each other so that displacements of the follower in two perpendicular directions cause displacements of the tracer which are also perpendicular,

but which are in a ratio of one to one over the square root of three to each other.

The linkage between the follower and the tracer is effected as described with reference to FIG. 1.

In the present embodiment, the table is provided along one of its sides with a fixed rule 2 along which a carriage 3 is slidable, the carriage being connected rigidly to a rule 4 extending perpendicularly to rule 3. Rule 4 carries two carriages 6 and 7 on which are respectively mounted followers 8 and 9. To carriage 6 is attached a rack 10 and to carriage 7 a rack 11. These racks engage respective sets of teeth 12a and 12b of a double pinion 12 which is rotatable about a shaft 13 mounted on a support 14 attached to rule 4. The ratio of the effective diameters of the sets of teeth 12a and 12b is one over the square root of three; this is therefore the same as the ratio between the displacements of the tracer and the follower parallel to rule 4.

A 45 set-square which is slidable on table 1, is attached by its hypotenuse to the rack 11 of carriage 7. A locking device 81 enables carriage 7 to be immobilised on rule 4 and the table is provided with an adjustable stop 82 for rule 4.

As regards height transfer, the apparatus may be used as follows:

A circle C of diameter D, such as the one drawn in the bottom right-hand corner of the table, is transformed, in isometric perspective, into an ellipse E the large axis of which is equal to D and the small axis of which is equal to the product of D and the square root of one third.

Any Straight line perpendicular to the plane of circle C is projected onto the isometric perspective parallel to the small axis of ellipse E, but lengths along this line are multiplied by the square root of two-thirds.

To draw the perspective of an object having lines situated in different but mutually parallel planes, such for example an object which includes a cylindro-conical body of maximum diameter D and a cylindrical shank, a flat view 83 of the said object is drawn or placed on a portion of the table situated to the left of stop 82, in projection in a plane perpendicular to the abovementioned parallel planes and oriented so that the direction of these planes is parallel to a short side 84 of set-square 80.

Rule 4 is then brought against stop 82 and then the side 84 of set-square 80 is position to be colinear with the direction 85 of one of the above-mentioned parallel planes. Carriage 7 is then locked on rule 4. Rule 4 is next moved back to the right and a point may then be drawn, under the tip of the follower, which will for example be the centre 86 of circle C which is contained by the plane of the direction bears the reference 85.

Circle C can then be drawn around centre 86 and with diameter D.

Rule 4 is then brought back against stop 82 and carriage 7 is freed. Side 84 of the set-square is positioned to be colinear with the direction 87 of the second parallel plane and carriage 7 is again locked on rule 4. Rule 4 is moved back to position follower 9 on line 88 parallel to rule 4 and passing through centre 86. This enables the centre 89 of circle C, situated in the second parallel plane to be determined. This circle is drawn.

Circle C situated at the end of the shank of the object and the tip 90 of the said object are then similarly drawn. The apparent contour of this object is obtained by constructing the tangents to circle C, through the tip 90, the tangents common to circles C and C, and tangents to circle C An auxiliary view 91 is thus drawn.

If H is the distance or height which separates two planes, for example those of which the directions are indicated by 85 and 87, it will be seen that, by construction, the distance which separates two homologous points of these planes in auxiliary view 91, for example the two centres 86 and 89, is equal to the product of H and the square-root of two.

To draw the perspective of the object it is sufficient to follow with the follower the lines of auxiliary view 91. In the perspective 92 drawn by the tracer, for example, the homologues 93 and 94 of centres 86 and 89 are separated by a distance equal to the product of H and the squre-root of two-thirds. In particular, the apparent contour of view 91 corresponds to the apparent contour of view 92 which dispenses with useless constructions and lines.

FIGS. 8 and 9 show how se-square 80 can be mounted on follower carriage 7.

This square is advantageously made of transparent plastics material and is hollow for lightness.

It is attached to carriage 7 by means of springs 95 each formed by a doubledover leaf as shown in FIG. 9 to form a loop shaped like a drop of water, of which one arm, which is shorter than the other, is fixed under the carriage while the second arm is fixed on the square. The set-square is applied to the table 1 when it is pressed downwardly, the spring normally lifting it above the table to avoid friction on movement of the carriage 7.

FIGS. and 11 show a construction of locking device 81. As shown, device 81 includes a yoke 96 attached to carriage 7 by means of bolts 97. In this yoke is mounted an eccentric shaft 98 which may be rotated by means of handle 99 which is mounted on it. The eccentric boss of shaft 98 pivots in a frame bearing a rubber block 100, rotation of which is prevented by a spring 101 attached to the yoke by means of bolt 102. In the position shownin FIG. 10, block 100 is applied against rule 4 and locks carriage 7 on said rule. To unlock the carriage, handle 99 is rotated in the direction of the arrow shown in FIG. 10.

FIGS. 12 and 13 show a construction of the adjustable stop 82 associated with rule 4.

This stop may be attached to table 1 in any position, by means of a clamp 103 which is tightened by means i of a screw 104 (FIG. 13). The stop 82 is hinged to the clamp about a shaft 105 extending parallel to the edge of the table so that it may either be placed on the table in an active position, as shown in solid lines in FIG. 13, or withdrawn by rotating about shaft 105 to drop it back over the edge of the table, as shown in broken lines. A handle 106 facilitates these manoeuvres, Rubber pads 107 deaden the impact of the stop on the fork of the clamp when it is withdrawn.

The adjustable stop member of stop 82 consists of an electro-magnet 108 which is slidable in a direction parallel to the direction of displacement of rule 4 in a housing of the stop body (FIG. 12). The position of this electromagnet is adjusted by means of a screw 109 which may be locked by means of a bolt 110. The electro-magnet cooperates with a plate 111 on rule 4. The electro-magnet may be deactivated by means of a circuit-breaker 112 carried by the stop.

The embodiment of FIG. 14 includes a table designed as described with reference to FIG. 5, in which the trac- 6 er-bearing carriage 6 and follower-bearing carriage 7 are mounted on parallel rules 22 and 23, displacements of these carriages being coordinated by means of a system of cables 26, 27 on drums 28, 29, 33, 34.

Carriage 7 which carries follower 9 also carries a setsquare which may be mounted as described with reference to FIGS. 8 and 9.

An adjustable stop 82 cooperates with rule 23.

Carriage 7 is locked on rule 23 by means of a brake 113 associated with drum 29. This drum also includes a clutch l 14 which enables the relative positions of the follower and the tracer to be adjusted.

The apparatus of the present embodiment is used in the same manner as that described with reference to FIG. 7. Height transfer is effected by means of a 45 view 83 and auxiliary view 91, to finally obtain a view 92.

The embodiments described above may be modified, particularly by substitution of equivalent technical means, without departing from the scope of the present invention.

What is claimed is:

1. Apparatus enabling the isometric perspective of an object to be drawn from flat views of the object including a fixed support on which flat views of the object to be drawn may be provided, a rotatable support for a drawing sheet, which may be placed in one of three angular positions spaced by a follower for following one of the flat views, a tracer which is displaceable over said rotatable support, and means linking said follower and said tracer such that displacements of said follower in two perpendicular reference directions cause displacements of said tracer which are perpendicular but in the ratio of one over the square root of three, wherein said linkage means between said follower and said tracer for displacements in that reference direction for which the displacements of said follower and said tracer are not equal comprises rotary means, the effective diameters of which are in the ratio to each other of one over the square root of three, said follower and said tracer being each mounted on a carriage movable along a rule which is movable perpendicularly to its length, said carriage of the follower carrying a member having an edge extending parallel to the plane of the table and oriented at 45 to the direction of displacement of the said carriage along said rule, the apparatus including a stop enabling said rule to be halted at a predetermined position and a locking device for immobilizing said carriage on said rule.

2. Apparatus according to claim 1, wherein said member consists of a 45 set square attached to the said carriage so that its hypotenuse is parallel to the rules.

3. Apparatus according to claim 2, wherein the set square is attached to the carriage by means of springs which lift it relative to the table.

41. Apparatus according to claim 1, wherein said stop is adjustably mounted on said table.

5. Apparatus according to claim 4, wherein said stop is withdrawable.

6. Apparatus according to claim 5, wherein said stop is adapted to immobilise said rule by magnetic action.

7. Apparatus according to claim 6, wherein said stop includes an electro-magnet cooperating with a magnetic element carried by the rule.

8. Apparatus according to claim 1, wherein said locking device includes a locking shoe controlled by an eccentric shaft.

9. Apparatus according to claim 1, wherein the said follower-bearing carriage and said tracer-bearing carriage are coupled by a system of cables and drums and said locking device consists of a brake acting on one of the drums.

10. A method of height transfer using apparatus according to claim 1, comprising providing on said table a flat view of the object to be drawn for which the mutually parallel planes in which the lines to be drawn are situated are perpendicular to the plane of the said view, said view being oriented such that the direction of said planes is parallel to said 45 edge, said follower bearing the object.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,786,567 Dated 2 1 7 Jean Louis D'angay, deceased, by Inv n 0r( Reqine Godard, Philippe Dangay, Catherine Dangay 7 It is certified'that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

[30] Foreign Application Priority Data:

June 12-,1972 France 72.21046 Signed and sealed this 17th day of September 1974.

(SEAL) Attest: I v

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM 304050 UscoMM-Dc 60376-P69 7 UIS. GOVERNMENT PRINTING OFFICE: 1959 Q355'334, 

1. Apparatus enabling the isometric perspective of an object to be drawn from flat views of the obJect including a fixed support on which flat views of the object to be drawn may be provided, a rotatable support for a drawing sheet, which may be placed in one of three angular positions spaced by 120*, a follower for following one of the flat views, a tracer which is displaceable over said rotatable support, and means linking said follower and said tracer such that displacements of said follower in two perpendicular reference directions cause displacements of said tracer which are perpendicular but in the ratio of one over the square root of three, wherein said linkage means between said follower and said tracer for displacements in that reference direction for which the displacements of said follower and said tracer are not equal comprises rotary means, the effective diameters of which are in the ratio to each other of one over the square root of three, said follower and said tracer being each mounted on a carriage movable along a rule which is movable perpendicularly to its length, said carriage of the follower carrying a member having an edge extending parallel to the plane of the table and oriented at 45* to the direction of displacement of the said carriage along said rule, the apparatus including a stop enabling said rule to be halted at a predetermined position and a locking device for immobilizing said carriage on said rule.
 2. Apparatus according to claim 1, wherein said member consists of a 45* set square attached to the said carriage so that its hypotenuse is parallel to the rules.
 3. Apparatus according to claim 2, wherein the set square is attached to the carriage by means of springs which lift it relative to the table.
 4. Apparatus according to claim 1, wherein said stop is adjustably mounted on said table.
 5. Apparatus according to claim 4, wherein said stop is withdrawable.
 6. Apparatus according to claim 5, wherein said stop is adapted to immobilise said rule by magnetic action.
 7. Apparatus according to claim 6, wherein said stop includes an electro-magnet cooperating with a magnetic element carried by the rule.
 8. Apparatus according to claim 1, wherein said locking device includes a locking shoe controlled by an eccentric shaft.
 9. Apparatus according to claim 1, wherein the said follower-bearing carriage and said tracer-bearing carriage are coupled by a system of cables and drums and said locking device consists of a brake acting on one of the drums.
 10. A method of height transfer using apparatus according to claim 1, comprising providing on said table a flat view of the object to be drawn for which the mutually parallel planes in which the lines to be drawn are situated are perpendicular to the plane of the said view, said view being oriented such that the direction of said planes is parallel to said 45* edge, said follower bearing rule against said stop, bringing said 45* into coincidence with the direction of one of said planes and locking said follower bearing carriage on said rule and then, by displacing said rule, transferring one or more points in this plane onto an auxiliary view on which the line or lines to be drawn appear in full-size, repeating the above process for each plane to draw an auxiliary view and, after release of said follower-bearing carriage, following this auxiliary view with the said follower, said tracer simultaneously drawing the perspective view of the object. 